1-Million droplet array with wide-field fluorescence imaging for digital PCR

Area of Science:

• Biotechnology
• Microfluidics
• Molecular Biology

Background:

• Digital droplet reactors enable picolitre/nanolitre volume analysis but struggle with large sample volumes and fragment counts typical in DNA assays.
• Existing methods often lack the high-throughput and high-dynamic-range needed for comprehensive molecular analysis.

Purpose of the Study:

• To develop an integrated droplet microfluidic platform with advanced fluorescence imaging for high-throughput, high-dynamic-range digital PCR.
• To overcome limitations of current digital droplet reactors for DNA-based assays.

Main Methods:

• Designed a microfluidic chip capable of generating over 1 million monodisperse 50 picolitre droplets in under 7 minutes.
• Integrated on-chip polymerase chain reaction (PCR) amplification and fluorescence detection.
• Utilized a 21-megapixel camera and macro-lens for wide-field fluorescence imaging of droplet arrays.

Main Results:

• Achieved generation of over 1 million droplets, self-assembling into 3D configurations for analysis.
• Demonstrated on-chip quantitative digital PCR (dPCR) using both end-point and real-time imaging.
• Reported a 100-fold increase in on-chip digitized reactors compared to previous technologies.

Conclusions:

• The developed integrated droplet microfluidic platform significantly enhances throughput and dynamic range for digital PCR assays.
• This system offers a powerful tool for precise quantification of nucleic acid content in complex biological samples.
• The platform paves the way for more advanced and efficient molecular diagnostics and research.